1. Technical Field
The present invention relates to a conjugate, which can be used for the preparation of dermatological and cosmetic compositions. The invention also relates to processes for preparing such conjugate and to its use.
2. Related Art
Dermatological or cosmetic compositions are used for example to protect skin against harmful external effects, such as against sun radiation. In modern society a more or less marked tanning of skin is considered to be attractive and an expression of dynamics and sportiveness. Besides this desired effect of sun on skin also a series of undesired side effects is occurring such as sunburn or premature aging of skin and wrinkling. Meanwhile a number of efficient UV filters has been developed which, applied onto the skin in the form of creams, lotions or gels, can inhibit effectively the development of sunburn even under a more intensive exposure to sun. The UV filters contained in the pharmaceutical or cosmetic preparations form a film and a layers respectively, on the surface of the skin. The known UV filters and sun protecting agents act in such manner that they absorb certain parts of sunlight so that this radiation cannot penetrate into deeper layers of the skin. It is known that the most dangerous part of the sun radiation is formed by the ultraviolet rays having a wavelength of less than 400 nm. The lower limit of the ultraviolet rays which reach the surface of earth by the absorption in the ozone layer is restricted to about 280 nm. The sun filters commonly used in the cosmetics absorb in a wavelength range of from 280 to 400 nm. This range comprises UVB rays having a wavelength between 250 and 320 nm which play a decisive roll in the formation of a sun erythema, as well as UVA rays having a wavelength between 320 and 400 nm which cause tanning but also aging of skin, promote the initiation of an erythematic reaction or increase this reaction with certain individuals or even may initiate phototoxic or photoallergic and irritative reactions.
Light protection formulations which have been applied onto the skin have the purpose to hold back skin damaging parts of radiation. As light filters inorganic or organic materials can be used.
Light protection formulations based on organic light filters contain organic light filters which are soluble in water and/or oil or are soluble neither in water nor in oil.
Light protection formulations having insoluble particulate organic light filters are described for example in WO 97/3643. The group of insoluble organic light filters is, however, restricted to a few classes of compounds.
Light protection formulations having organic light filters and being soluble in water and/or oil are described in publications DE-A-197 46 654, DE-A-197 55 504, EP-A-709 080, EP-A-775 698, EP-A-893 119 and U.S. Pat. No. 5,882,632.
In DE-A-197 46 654 the use of 4,4-diaryl-butadiene derivatives as soluble organic light filters in light protection formulations for protecting the skin against UVA radiation is described.
The above mentioned light protection formulations must contain the organic light filters in a high concentration in order to ensure a sufficient light protection. However, the most serious disadvantage of organic soluble light filters consists in that optionally they penetrate into the skin due to their solubility and can cause skin damages or allergies.
In JP-A-11-255 630 a light protection formulation for protecting the skin against UVA radiation is described which contains a dibenzoyl methane derivative and is applied to a silicone polymer-coated inorganic support. However, the preparation of this light protection formulation is troublesome and time consuming due to a multitude of operations. Furthermore, dibenzoyl methane derivatives are not photostable (light-resistant).
Dermatological and cosmetic compositions can further contain a multitude of active substances, such as organic substances having antioxidative and/or radical inhibiting properties as well as repellents.
In general, a heterogenisation of the active substances contained in dermatological and cosmetic compositions is desirable, since i.a. a penetration into the skin and a possibly resulting skin damage or allergy can be prevented.
It is an object of the present invention to provide a conjugate based on organic active substances and which cannot penetrate into the skin.
This object is achieved according to the present invention by providing a conjugate which comprises an inorganic pigment and an active substance based on organic compounds, the active substance being covalently bound through a spacer group to the inorganic pigment. The conjugate of the invention is characterized in that the spacer group contains a silicon atom or an aluminum atom.
The invention also provides a dermatological or cosmetic composition comprising at least one conjugate of the above mentioned type and at least one cosmetically, pharmaceutically and/or dermatological compatible vehicle and/or adjuvant.
In the frame of the present invention the expression xe2x80x9cconjugatexe2x80x9d means a product which is obtained by a molecular i.e. covalent bond between the active substance and the inorganic pigment. The expression xe2x80x9cactive substancexe2x80x9d comprises for example light absorbing organic compounds, substances having antioxidative and/or radical inhibiting properties, repellants, preservatives and derivatives of these active substances which can be bound covalently through a spacer group to an inorganic pigment. The active substance or derivative thereof comprises preferably a nucleophilic group. It is preferred that the active substance per se, i.e. without being bound to an inorganic pigment is water soluble and/or oil soluble.
The conjugate of the invention contains an inorganic pigment. In the frame of the present invention the expression xe2x80x9cpigmentxe2x80x9d means a dye (colorant) or filler being insoluble in the application medium. The inorganic pigment in the conjugate of the invention preferably is a metal oxide or a semi-metal oxide.
Examples of inorganic pigments comprise oxides, silicates, phosphates, carbonates, sulfates and nitrides, oxides being preferably used.
Preferred inorganic pigments comprise magnesium oxide, aluminum oxide, silicon dioxide, zinc oxide, cerium oxide, titanium dioxide, zirconium oxide, manganese oxide, boron oxide, red or black iron oxide, talc, kaolin, natural and synthetic mica materials, such as muscovite, phlogopite, lepidolite, biotite and vermiculite, magnesium carbonate, calcium carbonate, aluminum silicate, barium silicate, calcium silicate, magnesium silicate, strontium silicate, barium sulfate, calcium sulfate, calcium phosphate, fluoroapatite, hydroxyapatite, ceramic powder, boron nitride, iron titanate, zeolite and mixtures thereof. Silicon dioxide, titanium dioxide, mica, talc and mixtures of the above mentioned pigments (in the following called xe2x80x9cmixed pigmentsxe2x80x9d) such as silicon dioxide/titanium dioxide are particularly preferably used.
Commercially available inorganic mixed pigments which can be used according to the invention comprise mixtures of titanium dioxide/mica, titanium dioxide/micaltin oxide, titanium dioxide/mica/iron oxides, titanium dioxide/mica/silicon dioxide, titanium dioxide/mica/carmine, mica/iron oxides/aluminum oxide, mica/iron oxides, titanium dioxide/mica/zinc oxide, titanium dioxide/mica/barium sulfate, mica/silicon dioxide and titanium dioxide/iron oxides/silicon dioxide. These mixed pigments are sold under the names Timiron(copyright), Soloron(copyright), Colarona(copyright), Dichrona(copyright), Microna(copyright), Micronaspher(copyright) and Ronaspher(copyright).
Light scattering pigments such as Ronaspher(copyright) LDP as well as nacreous pigments can also be used.
The silicates can have a chain, belt or sheet-shaped structure. Silicates having a sheet-shaped structure such as mica or talc are preferably used.
The form in which the metal odor semi-metal compound is present, is not restricted to certain forms.
The metal or semi-metal compound has preferably the form of spherical particles. Suitable materials based on silicon dioxide comprise commercially available products offered under the name Monospher(copyright), such as Monospher(copyright) 10 (silicon dioxide having a particle size of 10 nm), Monospher(copyright) 25 (silicon dioxide having a particle size of 25 nm), Monospher(copyright) 100 (silicon dioxide having a particle size of 100 nm) or Monospher(copyright) 500 (silicon dioxide having a particle size of 500 nm), or Ronaspher(copyright) (silicon dioxide having a particle size of from 50 nm to 3 xcexcm).
The preparation of monodisperse spherical oxide particles is known. According to the process described in EP-A-216 278 monodisperse spherical oxide particles can be obtained by hydrolytic polycondensation of alkoxides.
Other preferred forms in which the metal or semi-metal compounds can be present comprise needles and flocs.
The active substances based on organic compounds which according to the invention are bound covalently to an inorganic pigment comprise for example light absorbing organic compounds, substances having antioxidative and/or radical inhibiting properties, repellants as well as preservatives. However, the active substances used according to the invention are not limited to these active substances.
The light absorbing organic compounds are selected from compounds which absorb UV light. Compounds are used which absorb UV light in the UVB range, i.e. in the range of from 280 to 320 nm and/or in the UVA range, i.e. in the range of from 320 to 400 nm.
UVB filters preferably exhibit a maximum of absorption in the range of from 300 to 320 nm and they can be selected from known substandes already described in the literature. Examples comprise derivatives of aminobenzoic acid, cinnamic acid, salicylic acids benzylidene camphor, phenyl benzimidazole, diphenyl-acrylate, triazine, triazole and vinyl group-containing amides.
Examples of aminobenzoic acid derivatives comprise 4-aminobenzoic acid, 4-aminobenzoic acid-2,3-dihydroxypropyl ester, 4-[bis(2-hydroxypropyl)-amino]benzoic acid ethylester, 4-(dimethylamino)benzoic acid-2-ethylhexylester (e.g. Eusolex(copyright) 6007) and ethoxylated 4-aminobenzoic acid ethylester (e.g. Uvinul(copyright) P25).
Examples of cinnamic acid derivatives comprise cinnamic acid esters like p-methoxy-cinnamic acid-2-ethylhexylester (e.g. Eusolex(copyright) 2292), 4-methoxy-cinnamic acid isopentylester, e.g. in the form of a mixture of the isomers (e.g. Neo Heliopan(copyright) E 1000) and 4-methoxy-cinnamic acid-2-methylhexylester, as well as the diethanolamine salt of 4-methoxy-cinnamic acid and cinnamic acid derivatives as described in U.S. Pat. No. 5,601,811 and in WO 97/851.
The salicylic acid derivatives include for example 2-ethylhexyl salicylate (e.g. Eusolex(copyright) OS), 4-isopropyl-benzylsalicylate (e.g. Megasol(copyright)) and 3,3,5-trimethylcyclohexyl-salicylate (e.g. Eusolex(copyright) HMS).
Examples for benzylidene camphor derivatives comprise 3-(4xe2x80x2-methyl-benzylidene)-dl-camphor (e.g. Eusolex(copyright) 6300), 3-benzylidene camphor (e.g. Mexory(copyright) SD), polymers of N-{(2- and 4)-[(2-oxoborn-3-ylidene)methyl]-benzyl}-acrylamide (e.g. Mexoryl(copyright) SW), N,N,N-trimethyl-4-(2-oxoborn-3-ylidenemethyl)anilinium methylsulfate (e.g. Mexoryl(copyright) SK) and xcex1-(2oxo-born-3-ylidene)toluene-4-sulfonic acid (e.g. Mexoryl(copyright) SL).
As examples of phenylbenzimidazole derivatives 2-phenylbenzimdazole-5-sulfonic acid and its potassium, sodium and triethanolamine salts can be mentioned (e.g. Eusolex(copyright) 232).
Special examples of diphenylacrylate derivatives comprise 2-cyano-3,3xe2x80x2-di-phenylacrylic acid-2-ethylhexylester and 2-cyano-3,3xe2x80x2-diphenylacrylic acid ethylester.
Examples of triazole derivatives comprise benzotriazoles, such as 2-(2-hydroxy-5-methylphenyl) benzotriazole as well as the triazoles described in EP-A-893 119.
Special examples of triazines comprise 2,4,6-tri-{4-[(2-ethylhexyl)oxycarbonyl]-phenylamino}-1,3,5-triazine as well as the compounds described in EP-A-893 119. Further examples comprise trianiline-triazine derivatives as disclosed in U.S. Pat. No. 5,332,568, EP-A-570 838, EP-A-517 104, U.S. Pat. No. 5,252,323, WO 93/17002 and WO 97/03642, hydroxyphenyltriazine derivatives as described in EP-A-775 698 as well as bis-resorcinol-dialkylaminotriazines as disclosed for example in EP-A-780 382.
Preferred examples of vinyl groups containing amide derivatives comprise those described in EP-A-893 119.
As UVA filter substances preferably compounds can be used which exhibit a maximum of absorption in the range of from 330 to 360 nm. Any known UVA filter substances like derivatives of benzophenone, dibenzoylmethane, diarylbutadiene and triazine can be used.
Special examples of benzophenone derivatives comprise 2-hydroxy-4-methoxybenzophenone (e.g. Eusolex(copyright) 4360), 2-hydroxy4-methoxybenzophenone-5-sulfonic acid and its sodium salt (e.g. Uvinul(copyright) MS-40), as well as 8-(2,2xe2x80x2-dihydroxy-4-meothxybenzophenone).
Special examples of benzoylmethane derivatives and dibenzoylmethane derivatives comprise 1-(4-tert-butylphenyl)3-(4-methoxyphenyl)-propane-1,3-dione (e.g. Eusolex(copyright) 9020) and 4-isopropyidibenzoylmethane (e.g. Eusolex(copyright) 8020).
Examples of diarylbutadiene derivatives comprise the 4,4-diarylbutadienes described in DE-A-197 46 654, in particular 4,4-diphenylbutadiene.
Special examples of triazines comprise 2,4-bis-{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine.
Further suitable UV filters comprise 2-cyano-3,3-diphenylacrylic acid-2-ethylhexylester (e.g. Eusolex(copyright) OCR), 3,3xe2x80x2-(1,4-phenylenedimethylene)-bis-(7,7-dimethyl-2oxobicyclo-[2.2.1]hept-1-ylmethanesulfonic acid and its salts (e.g. Mexoryl(copyright) SX), 2,4,6-trianilino-(p-carbo-2xe2x80x2-ethylhexyl-1xe2x80x2-oxy)-1,3,5-triazine (e.g. Uvinul(copyright) T 150), 2-(2H-benzotriazole-2-yl)4-methyl-6-(2-methyl-3-(1,3,3,3-tetramethyl-1-(trimethylsilyloxy)disiloxanyl)propyl)-phenol (e.g. Silatrizole(copyright)), 4,4xe2x80x2-[(6-[4-((1,1-dimethyl-ethyl)aminocarbonyl)-phenylamino]-1,3,5-triazine-2,4-diyl)diimino]bis(benzoic acid-2-ethylhexylester) (e.g. Uvasorb(copyright) HEB), xcex1-(trimethylsilyl)-xcfx89-[trimethylsilyl)oxy]poly[oxy-(dimethyl [and about 6% methyl[2-[p-[2,2-bis(ethoxycarbonyl]vinyl]phenoxy]-1-methylene-ethyl] and ca, 1.5% methyl[3-[p-[2,2-bis(ethoxycarbonyl)vinyl)phenoxy)-propenyl) and 0.1 to 0.4% (methylhydrogen]silylene]] (n≈60) (CAS-No. 207 574-74-1), 2,2xe2x80x2-methylene-bis-(6-(2H-benzotriazole-2-yl)4-(1,1,3,3-tetramethylbutyl)phenol) (CAS-No. 103 597-45-1), 2,2xe2x80x2-(1,4-phenylene)-bis-(1H-benzimidazole-4,6-disulfonic acid, monosodium salt) (CAS-No. 180 898-37-7) and 2,4-bis-{[(2-ethyl-hexyloxy)-2-hydroxyl]-phenyl}-6-(4-methoxy-phenyl)-1,3,5-triazine (CAS-No. 103 597-45-, 187 393-00-6).
Preferred UV radiation absorbing organic compounds are 3-(4xe2x80x2-methyl-benzylidene)-dl-camphor, 1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)-propane-1,3-dione, 4-isopropyl-dibenzoylmethane, 2-hydroxy-4-methoxy-benzophenone, methoxycinnamic acid octylester, methoxycinnamic acid octylester, 3,3,5-trimethylcyclohexyl-salicylate, 4-(dimethylamino)-benzoic acid-2-ethylhexylester, 2-cyano-3,3-diphenylacrylic acid-2-ethylhexylester, 2-phenylbenzimidazole-5-sulfonic acid as well as its potassium, sodium and triethanolamine salts.
Photostable UV radiation absorbing organic compounds are preferably used, photostabile UVA filters and UVB filters being particularly preferably used.
Suitable substances having antioxidative and/or radical inhibiting properties comprise for example flavonoides, coumaranones, amino acids (e.g. glycine, histidine, tyrosine, tryptophane) and derivatives thereof, imidazoles, (e.g. urocaninic acid) and derivatives thereof, peptides such as D,L-camosine, D-camosine, L-camosine and derivatives thereof (e.g. anserine), carotinoides, carotines (e.g. xcex1-carotine, xcex2-carotine, lycopine) and derivatives thereof. chlorogenic acid and derivatives thereof, liponic acid and derivatives thereof (e.g. dihydroliponic acid), aurothioglucose, propylthiouracile and other thioles (e.g. thioredoxine, glutathione, cysteine, cystine, cystamine and the glycosyl, N-acetyl, methyl, ethyl, propyl, amyl, butyl and lauryl, palmitoyl, oleyl, xcex3-linoleyl, cholesteryl and glyceryl esters thereof), diaurylthiodipropionate, distearylthiodipropionate, thiodipropionic acid and derivatives thereof (esters, ethers, peptides, lipides, nucleotides and nucleosides) as well as sulfoximine compounds (e.g. buthionine sulfoximines, homocysteine sulfoximine, buthionine sulfones, penta, hexa, heptathionine sulfoximine), chelating agents (e.g. xcex1-hydroxy fatty acids, palmitic acid, phytinic acid, lactoferrin), xcex1-hydroxy acids (e.g. citric acid, lactic acid, malic acid), huminic acid, gailic acid, gall extracts, bilirubin, biliverdin, EDTA, EGTA and derivatives thereof, unsaturated fatty acids and derivatives thereof, vitamin C and derivatives (e.g. ascorbyl palmitate, ascorbyl acetate), tocopheroles and derivatives (e.g. vitamin E acetate), vitamin A and derivatives (e.g. vitamin A palmitate) as well as coniferyl benzoate of benzoic resin, rutinic acid and derivatives thereof, xcex1-glycosylrutin, ferula acid, furfurylidene glucitol, carnosine, butylhydroxytoluene, butylhydroxyanisol, nordohydroguajaretic acid, trihydroxybutyrophenone, quercitin, ureic acid and derivatives thereof, mannose and derivatives thereof vitamin E and derivatives thereof, stilbenes and derivatives thereof (e.g. stilbene oxide, trans-stilbene oxide) as well as BHT (2,6-di-tert-butyl-4-methyl-phenol).
Preferred antioxidants comprise flavonoides, coumaranones, vitamins and BHT.
The glucosides of flavanones, flavones, 3-hydroxyflavones (=flavanoles), aurones, isoflavones and rotenoides are considered as flavanoides (Rxc3x6mpp Chemie Lexikon, Vol. 9, 1993). However, in the frame of the present invention they also comprise the aglycones, i.e. the sugar-free components and the derivatives of flavonoides and aglycones. In the frame of the present invention the coumaranones also comprise their derivatives.
Preferred flavonoides are derived from flavanones, flavones, 3-hydroxyflavones, aurones and isoflavones, in particular from flavanones, flavones, 3-hydroxyflavones and aurones.
The flavanones are characterized by the following basic structure: 
The flavones are characterized by the following basic structure: 
The 3-hydroxyflavones (flavonoles) are characterized by the following basic structure: 
The isoflavones are characterized by the following basic structure: 
The aurones are characterized by the following basic structure: 
The coumaranones are characterized by the following basic structure: 
Preferably the flavonoides and coumaranones are selected from the compounds of formula (1): 
wherein
Z1 to Z4 independently each represent H, OH, alkoxy, hydroxyalkoxy, mono- or oligoglycoside radicals, wherein the alkoxy and hydroxyalkoxy groups can be branched and straight and contain from 1 to 18 carbon atoms and wherein also sulfate or phosphate can be bound to the hydroxy groups of the named radicals,
A is selected from the group consisting of the partial formulae (1A), (1B) and (1C) 
Z5 represents H, OH or OR,
R represents a mono- or oligoglycoside radical,
Z6 to Z10 have the meanings of the radicals Z1 to Z4 and 
The alkoxy groups are preferably linear and contain from 1 to 12, preferably from 1 to 8 carbon atoms. These groups thus correspond to the formula xe2x80x94Oxe2x80x94(CH2)mxe2x80x94H, wherein m ist 1,2,3,4,5,6,7 or 8 and in particular 1 to 5.
The hydroxyalkoxy groups are preferably linear and contain from 2 to 12, preferably from 2 to 8 carbon atoms. These groups thus correspond to the formula xe2x80x94Oxe2x80x94(CH2)nxe2x80x94OH, wherein n is 2,3,4,5,6,7 or 8, in particular 2 to 5 and particularly preferred 2.
The mono- and oligoglycoside radicals preferably are constituted of 1 to 3 glycoside units. Preferably these units are selected from the group consisting of hexosyl radicals, in particular rhamnosyl radicals and glucosyl radicals. But also other hexosyl radicals, for example allosyl, altrosyl, galactosyl, gulasyl, idosyl, mannosyl and talosyl can be optionally used with advantage. It can also be advantageous to use pentosyl radicals.
In a preferred embodiment
Z1 and Z3 represent H,
Z2 and Z4 have another meaning than H, in particular represent OH, methoxy, ethoxy or 2-hydroxyethoxy,
Z5 represents H, OH or a glycoside radical being constituted of 1 to 3, preferably 1 or 2 glycoside units,
Z6, Z9 and Z10 represent H and
Z7 and Z8 have another meaning than H, in particular represent OH, methoxy, ethoxy or 2-hydroxyethoxy.
Particularly preferred compounds are represented by the following general formula: 
wherein
xe2x80x94Xxe2x80x94 represents a single bond, xe2x80x94CH2xe2x80x94 or xe2x95x90CHxe2x80x94 and
R1, R2, R3 and R4 which can be identical or different, independetly represent H,
straight or branched C1-C12-alkyl groups and/or -alkylcarbonyl groups,
straight or branched C3-C12-alkenyl groups and/or -alkenylcarbonyl groups,
straight or branched C1-C12-hydroxyalkyl- and/or -hydroxyalkylcarbonyl groups wherein the hydroxy group can be bound to a primary or secondary carbon atom of the chain and wherein the alkyl chain can also be interrupted by oxygen,
C3-C10-cycloalkyl- and/or -cycloalkylcarbonyl groups and C3-C12-cycloalkenyl- and/or -cycloalkenylcarbonyl groups wherein the rings can also be bridged (linked) by xe2x80x94(CH2)n-groups wherein n is 1 to 3,
aryl groups and/or arylcarbonyl groups heteroaryl groups and/or heteroarylcarbonyl groups,
wherein these groups can be substituted by alkyl, hydroxy, alkoxy, amino, mono- and dialkylamino, sulfonic acid, carboxylic and/or halogen groups,
mono- or oligoglycoside radicals, 
wherein R5 represents tert, -butyl or isopropyl and
Me represents a proton or an alkaline metal ion, in particular a potassium ion.
The radicals thus can be bound to the basic body as ethers or as esters.
In a further preferred embodiment the flavonoides are selected from the following compounds, 4,6,3xe2x80x2,4xe2x80x2-tetrahydroxyauron, quercetin, rutin, isoquercetin, anthocyanidin (cyanidin), eriodictyol, taxifolin, luteolin, trishydroxyethylquercetin (troxequercetin), trishydroxyethylrutin (troxerutin), trishydroxyethylisoquercetin (troxeisoquercetin) as well as trishydroxyethylluteolin (troxeluteolin).
Preferred flavonoides are in particular rutin and troxerutin. Particularly preferred is troxerutin.
Preferred among the coumaranones is 4,6,3xe2x80x2,4xe2x80x2-tetrahydroxybenzyl-coumaranone-3.
Suitable repellants comprise amides and derivatives thereof, in particular N,N-diethyl-3-methyl-benzamide, 3-[N-n-butyl-N-acetyl]-aminopropionic acid ethylester (IR3535(copyright)) and N,N-caprylic acid diethylamide (IR790(copyright)).
Suitable preservatives comprise benzalkonium chloride, benzoic acid and salts thereof (such as sodium benzoate), methylparaben, ethylparaben, propylparaben, sorbic acid and salts thereof (such as potassium sorbate), cetylpyridinium chloride, cetrimonium chloride as well as salicylic acid and salts thereof (such as sodium salicylate).
The active substance used according to the invention can also be an antiphlogistic substance.
The active substance used according to the invention preferably is soluble in oil and/or water and by the covalent bond to an inorganic pigment it is transferred into a condition in which it can no more penetrate into the skin.
Preferred conjugates of the invention are represented by the following general formula: 
wherein:
R1 represents the covalently bound active substance-group,
A represents O, S or NH,
B represents a straight or branched alkylene group having up to 20, preferably from 1 to 12, particularly preferably from 3 to 12 carbon atoms,
C represents a straight or branched alkyleneoxy group having up to 20, preferably from 1 to 12, particularly preferably from 3 to 12 carbon atoms, wherein the oxygen atom of the alkyleneoxy group is bound to group B,
Me represents a silicon atom or an aluminum atom.
a represents 0 or 1,
b represents 0 or 1 and
c represents 0 or 1.
The silicon atom and aluminum atom, respectively, can form one or more covalent bonds to the inorganic pigment and/or to the active substance-group.
Preferred examples of R1 comprise, besides the above named substances: 
wherein n is 0, 1 or 2 and * is a bond to the spacer group.
In the following the preparation of the conjugate of the invention is described.
For preparing the conjugate of the invention the active substance is covalently bound through a spacer group (linking group) to an inorganic pigment. In the frame of the present invention the expression xe2x80x9cspacer groupxe2x80x9d means a monomeric or oligomeric compound group, however, no polymeric group.
The spacer group is preferably a linking group represented by the following formula:
*xe2x80x94(A)a(B)b(C)c(A)axe2x80x94Mexe2x80x94Oxe2x80x94+
wherein:
A represents O, S or NH,
B represents a straight or branched alkylene group having up to 20, preferably from 1 to 12, particularly preferably from 3 to 12 carbon atoms,
C a straight or branched alkyleneoxy group having up to 20, preferably from 1 to 12, particularly preferably from 3 to 12 carbon atoms, wherein the oxygen atom of the alkyleneoxy group is bound to group B,
Me represents a silicon atom or an aluminum atom,
a is 0 or 1,
b is 0 or 1,
c is 0 or 1,
* represents the bond to the active substance-group and
+ represents the bond to the inorganic pigment.
The conjugate of the invention can be prepared by first reacting a compound having a silicon atom or an aluminum atom and containing at least two terminal reactive groups with the active substance based on organic compounds in order to covalently bind both compounds through one of the two reactive groups. The obtained intermediate product then is reacted with the inorganic pigment in order to covalently bind the intermediate product through the other reactive group to an inorganic pigment. 
wherein Z represents a group which can be split off, for example a halogen atom (preferably Cl) or an alkoxy group.
Examples of the active substance-group R1 comprise the groups mentioned above.
1-(4-tert-Butylphenyl)-3-(4-allyloxyphenyl)propane-1,3-dione (a Eusolex(copyright) 9020 analogue), for example, can be reacted with triethoxysilane as follows: 
The silylated intermediate product then is covalently bound to an inorganic pigment such as silicon dioxide. The ethoxy groups of the intermediate product react with the hydroxy groups bound to the surface of the silicon dioxide by splitting off ethanol. 
This variant has the advantage that the intermediate products can be purified and thus a higher chemical purity of the final product can be obtained.
Alternatively, the conjugate of the invention can be prepared by first reacting a compound having a silicon atom or an aluminum atom and containing at least two terminal reactive groups with an inorganic pigment in order to covalently bind the compound and the pigment through one of both reactive groups. The obtained intermediate product then is reacted with the active substance based on organic substances in order to covalently bind the intermediate product through the other reactive group to the active substance. This variant has preparative advantages (starting with high excesses of reagents, easy recovery etc.).
It is also possible to bind at first the inorganic pigment to suitable, commercially available silicon compounds. In this way a multitude of differently functionalized particles can be obtained. Lateron the single functionalities can be used to form the conjugates.
In this way the following conjugates for example can be obtained: (in the following formulae the group R represents an alkyl group and the group X represents a group which can be split off). 
Alternatively, in a first step the coupling of A with B can be carried out. In a second step then it can be bound to the inorganic pigment.
The synthesis of the conjugate of the invention is carried out in an inert solvent which is selected dependent on the used starting materials. If for example an alkoxysilane is used, the corresponding alcohol is preferably used as the solvent.
The number of the reactive groups, such as hydroxy groups, at the surface of the inorganic pigment can be increased by the process described in DE-A-198 02 753.
Inorganic support materials depending on the chemical structure exhibit at the surface a more or less large number of reactive OH groups which can form a chemical bond. This number is for example about 4.4 to 8.5/nm2 for completely hydroxylated SiO2 monospheres (H. P. Boehm. xe2x80x9cAngew. Chem.xe2x80x9d 78, 617 (1966)). These values were confirmed by J. Kratochvila et al., xe2x80x9cJournal of Non-Crystalline Solidsxe2x80x9d 143, 14-20 (1992). At a bonding distance of about 0.16 nm for the Sixe2x80x94O bond and at an angle of 150xc2x0 for the Sixe2x80x94Oxe2x80x94Si angle there are about 13 Si atoms/nm2 at the surface of the SiO2 monospheres. This means, that in the superficial monolayer a maximum of 13 Sixe2x80x94OH groups can be present with an additional triple valence bonding of the Si through the oxidic oxygen bridges. However, normally in SiO2 monospheres which have been dried at room temperature, only 4 Sixe2x80x94OH groups can be expected (see Boehm and Kratochvila).
In order to obtain an number of active Sixe2x80x94OH groups as large as possible on the SiO2 monospheres per weight unit the surfaces of the SiO2 monospheres can be increased in the form of pores, gaps and/or by particle diameters which are as small as possible. By increasing the number of the Sixe2x80x94OH groups by saturating with water or steam no sufficient solution is obtained, since the water additionally adsorbed at the surface causes hydrolysis of most of the chemisorptive bonds of the surface to ligands. On the other hand, intensive drying leads to a decrease of the number of the Sixe2x80x94OH groups to lower than 2 per nm2.
According to the process described in DE-A-198 02 753 for example an oxide or silicate in an inert aprotic solvent such as THF, DMF, cyclohexane or toluene is treated with a strongly basic reagent such as an alkaline metal or alkaline earth metal hydroxide, a hydride or an alcoholate in order to split the superficial oxide bondings of the oxide or silicate, and then the treated oxide or silicate is treated with an inorganic or organic acid to form additional hydroxy groups.
When inorganic pigments used according to the invention are treated according to this process, the bond density of the active substances to the surface of the inorganic pigment can be increased.
The particle size of the conjugate of the invention is not limited to a certain particle size; normally, however, it lies within a range of from 1 nm to 250 xcexcm, preferably in a range of from 1 nm bis 1 xcexcm and particularly preferably in a range of from 5 nm to 100 nm, in order to ensure an optimal distribution on the skin.
The conjugate of the invention can be dried after its preparation and then it can be introduced into the dermatological or cosmetic composition or it can be introduced into the dermatological or cosmetic composition in the form of a dispersion, for example dispersed in a cosmetic oil or liquid light filter.
Suitable oil components comprise natural and synthetic substances like paraffin oil, glycerylstearate, isopropylmyristate, diisopropyladipate, 2-ethylhexanoic acid-acetylstearylester, hydrogenated polyisobutene, vaseline, caprylic acid/caprlnic acid-triglycerides, microcrystalline wax, lanolin, mineral oils, mineral waxes, esters of fatty acids with alcohols like isopropanol, propyleneglycol or glycerine, alkylbenzoates, silicone oils like dimethylpolysiloxanes, diethylpolysiloxanes or diphenylpolysiloxanes, stearic acid, light filters which are present in liquid form as well as vitamin K1. Preferred examples comprise ethylbutylacetylaminopropionate (IR 3535(trademark)), butyleneglycol-dicaprylate/dicaprinate (Miglyol 8810), propyleneglycol-dicaprylate/dicaprinate, C12-15-alkyibenzoates, isopropylmyristate, caprylic acid/caprinic acid-triglycerides, octylpalmitate, almond oil, avocado oil, jojoba oil, isostearylisostearate, octyldodecanol, dibutyladipate (Cetiol B), coco acid-glycerides (Myritol 331), dicaprilylether (Cetiol OE), isostearyl-neopentanoate (Ceraphyl 375), C12-15-alkyllactates (Ceraphyl 41), diortylmalate (Ceraphyl 45) as well as the liquid light filters Eusolex(copyright) 2292, Eusolex(copyright) OCR, Eusolex(copyright) 6007, Eusolex(copyright) HMS and Eusolex(copyright) OS.
The dermatological or cosmetic composition of the invention contains the conjugate described above or a combination of the conjugates described above with at least one cosmetically, pharmaceutically and/or dermatologically compatible vehicle and/or adjuvant. Of course, the dermatological or cosmetic composition can also contain the conjugate of the invention in combination with other active substances like organic or inorganic UVA and UVB filters, IR or VIS filters. Particularly preferred is the combination with further UV filters comprising the unbound light filters described above or mixtures thereof. The ratio between the bound active substances (i.e. the active substances which are bound to pigments) and the unbound active substances (i.e. the active substances which are not bound to pigments) preferably lies within a range of from 1:10 to 10:1 and particularly preferred in a range of from 1:5 to 5:1. For example, light filters bound to pigments can be combined with unbound light filters.
The dermatological or cosmetic composition of the invention contains the conjugate of the invention optionally in combination with further cosmetic substances, preferably in an amount in the range of from 0.05 to 30% by weight, particularly preferred in an amount in the range of from 0.5 bis 10% by weight and especially preferred in an amount in the range of from 0.6 to 6% by weight, based on the total weight of the dermatological or cosmetic composition.
Definitions of the Cosmetic Substances
Examples of inorganic UV filters comprise coated titanium dioxide (e.g.
Eusolex(copyright) T-2000 or Eusolex(copyright) T-AQUA), zinc oxides (e.g. Sachtotec(copyright)), iron oxides and cerium oxides. These inorganic UV filters are incorporated into the dermatological or cosmetic compositions of the invention usually in an amount of from 0.5 to 10% by weight, preferably from 2 to 5% by weight.
Examples of vehicles and adjuvants comprise thickening agents, softening agents, humectants, surfactants, emulgators, preservatives, antifoaming agents, perfums, fats and waxes, lanolin, propellants, stabilizers, antioxidants, bactericides, dyes and/or pigments which color the formulation per se or the skin, film forming agents, odor improvers, complexing agents and other usual additives used in cosmetics.
As dispersant and solubilizer, respectively, a cosmetic oil, a wax or another fatty body, an alcohol or a polyol or mixtures thereof can be used. Particularly preferred alcohols or polyols are ethanol, i-propanol, propylenglycol. glycerine and sorbitol.
As emulgators preferably known W/O emulgators, but also O/W emulgators like polyglycerine esters, sorbitane esters or partially esterified glycerides can be used.
Typical examples of fats comprise glycerides and as waxes for example bees wax, carnauba wax, paraffin wax or microwaves can be used, optionally in combination with hydrophilic waxes.
As stabilizers metal salts of fatty acid like magnesium, aluminum and/or zinc stearate can be used.
Suitable thickening agents are for example cross-linked polyacrylic acids and derivatives thereof, polysaccharides, in particular xanthan gum, guar-guar, agar-agar, alginates and tyloses, carboxymethylcellulose and hydroxyethyl-cellulose, further fatty alcohols, monoglycerides and fatty acids, polyacrylates, polyvinylalcohol and polyvinylpyrrolidons.
Usable film forming agents comprise hydrocolloides, such as chitosan, microcrystalline chitosan or quaternary chitosan, polyvinylpyrrolidone, vinylpyrrolidone-vinylacetate copolymers, polymers of the acrylic acid series, quaternary cellulose derivatives and similar compounds.
Suitable preservatives are for example formaldehyde solutions, p-hydroxy-benzoate or sorbic acid.
As nacreous agents for example glycoldistearic acid esters such as ethylene-glycol-distearate, but also fatty acids and fatty acid monoglycolesters are usable.
As dyes substances which are suitable and admitted for cosmetic purposes can be used as listed for example in the publication xe2x80x9cKosmetische Fxc3xa4rbemittelxe2x80x9d of the Farbstoffkommission der Deutschen Forschungsgemeinschaft, published in Verlag Chemie, Weinheim, 1984.
As antioxidants for example amino acids, imidazoles, peptides, carotinoides, xcex1-hydroxy acids, unsaturated fatty acids, vitamin A, C and/or E and suitable derivatives of these substances can be used as well as zinc and its compounds (like ZnO, ZnSO4) or selenium and its compounds (like selenium methionine). Preferred antioxidants comprise the substances mentioned above having antoxidative properties, where flavonoides, coumaranones, vitamins and BHT are preferred.
Mixtures of antioxidants can also be used in the dermatological and cosmetic compositions of the invention. Known and commercially available mixtures comprise mixtures which contain as active ingredients lecithin, L-(+)-ascorbylpalmitate and citric acid (e.g. Oxynex(copyright) AP), natural tocopherols, L-(+)-ascorbylpalmitate, L-(+)-ascorbic acid and citric acid (e.g. Oxynex(copyright) K LIQUID), tocopherol extracts from natural sources, L-(+)-ascorbylpalmitate, L-(+) ascorbic acid and citric acid (e.g. Oxynex(copyright) L LIQUID), DL-xcex1-tocopherol, L-(+)-ascorbylpalmitate, citric acid and lecithin (e.g. Oxynex(copyright) LM) or BHT, L-(+)-ascorbylpalmitate and citric acid (e.g. Oxynex(copyright) 2004).
In a preferred ambodiment the flavonoides are selected from the following compounds: 4,6,3xe2x80x2,4xe2x80x2-tetrahydroxyauron, quercetin, rutin, isoquercetin, anthocyanidin (cyanidin), eriodictyol, taxifolin, luteolin, trishydroxyethylquercetin (troxequercetin), trishydroxyethylrutin (troxerutin), trishydroxyethyl-isoquercetin (troxeisoquercetin), trishydroxyethylluteolin (troxeluteolin) as well as sulfates and phosphates.
Among the flavonoides rutin and troxerutin are particularly preferred. Especially preferred is troxerutin.
Among the coumaranones 4,6,3xe2x80x2,4xe2x80x2-tetrahydroxy-benzylcoumaranone-3 as well as it salts (sulfate, phosphate) are preferred.
The dermatological or cosmetic composition of the invention can contain as further ingredients vitamins. Preferably vitamins and vitamin derivatives selected from vitamin A, vitamin A propionate, vitamin A palmitate, Vitamin A acetate, retinol, vitamin B, thiaminechloride-hydrochloride (vitamin B1), riboflavin (vitamin B2), nicotic acid amide, vitamin C (ascorbic acid), vitamin D, ergocalciferol (vitamin D2), vitamin E, DL-xcex1-tocopherol, tocopherol E acetate, tocopherol-hydrogensuccinate, vitamin K1, esculin (active substance of vitamin P), thiamine (vitamin B1), nicotinic acid (niacin), pyridoxin, pyridoxal, pyridoxamine, (vitamin B6), panthothenic acid, biotin, folic acid and cobalamin (vitamin B12), are contained in the dermatological or cosmetic compositions of the invention, particularly preferred are vitamin A palmitate, vitamin C, DL-xcex1-tocopherol, tocopherol E acetate, nicotinic acid, pantothenic acid and biotin.
Optionally the dermatological or cosmetic compositions of the invention can also contain one oder more chemical substances having self-tanning properties.
As chemical substances having self-tanning properties all natural and synthetic substances which are suitable for the preparation of cosmetic formulations and which ate known to the expert can be used. These can be both plant extracts and synthetic self-tanning agents like dihydroxyacetone or xcex1-ketoles as well as erythrolose.
Application forms of the dermatological or cosmetic compositions of the invention comprise: suspensions, emulsions, fat sticks, pastes, ointments, creams or milk (O/W, W/O, O/W/O, W/O/W), lotions, powders, soaps, tenside containing cleansing preparations, oils, aerosols, sprays as well as oily-alcoholic, oily-aqueous or aqueous-alcoholic; gels and solutions, respectively. Further application forms are for example sticks, shampoos and shower baths.
The aqueous phase of the dermatological or cosmetic compositions of the invention preferably contains alcohols, diols or polyols as well as ethers, preferably ethanol, isopropanol, 1,2-propandiol, propyleneglycol, glycerine, ethyleneglycol, ethyleneglycolmonoethyl- or -monobutylether or analogous products, further one or more thickener, such as silicon dioxide, aluminum silicates, polysaccharides and derivatives thereof, e.g. hyaluronic acid, xanthan gum, hydroxypropylmethylcellulose or a polyacrylate selected from the group of the so-called carbopoles.
Usable oil components comprise the oil components described above.
Ointments, pastes, creams and gels can contain usual vehicles such as animal and plant fats, waxes, paraffins, starch, tragacanth, cellulose derivatives, polyethylene glycols, silicones, bentonites, silicic acid, talc and zink oxide or mixtures of these substances.
Powders and sprays can contain usual vehicles such as milk sugar, talc, silicic acid, aluminum hydroxide, calcium silicate and polyamide powder or mixtures of these substances. Sprays can additionally contain usual propellants, such as chlorfluorohydrocarbons, propane/butane or dimethylether.
Solutions and emulsions can contain usual vehicles such as solvents, solubilizers and emulgators, e.g. water, ethanol, isopropanol, ethylcarbonate, ethylacetate, benzylalcohol, benzylbenzoate, propylene glycol, 1,3-butylglycol, oils, in particular cotonseed oil, peanut oil, cornseed oil, olive oil, castor oil and sesame oil, glycerine fatty acid esters, polyethylene glycols and fatty acid esters of sorbitan or mixtures of these substances.
Suspensions can contain usual vehicles such as liquid diluents, e.g. water, ethanol or propylene glycol, suspending agents like ethoxylated isostearyl alcohols, polyoxyethylene sorbitolesters and polyoxyethylene sorbitanesters, microcrystalline cellulose, aluminum-meta-hydroxide, bentonite, agar-agar and tragacanth or mixtures of these substances.
Soaps can contain usual vehicles like alkali salts of fatty acids, salts of fatty acid semi-esters, fatty acid proteinhydrolysates, isothionates, lanolin, fatty alcohol, plant oils, plant extracts, glycerine, sugars or mixtures of these substances.
Tenside containing cleansing products can contain usual vehicles such as salts of fatty alcohol sulfates, fatty alcohol ethersulfates, sulfosuccinic acid semi-esters, fatty acid proteinhydrolysates, isothionates, imidazolinium derivatives, methyltaurates, sarcosinates, fatty acid amide-ethersulfates, alkylamido-betaines, fatty alcohols, fatty acid glycerides, fatty acid diethanolamides, plant oils and synthetic oils, lanolin derivatives, ethoxylated glycerine fatty acid esters or mixtures of these substances.
Face and body oils can contain usual vehicles such as synthetic oils like fatty acid esters, fatty alcohols, silicone oils, natural oils like plant oils and oily plant extracts, paraffin oils, lanolin oils or mixtures of these substances. Preferred examples of such verhicles comprise the oil components mentioned above.
In a preferred embodiment the dermatological or cosmetic composition according to the invention is an emulsion being present in the form of a protection cream or milk and comprising in addition to the conjugate of the invention fatty alcohols, fatty acids, fatty acid esters, in particular triglycerides of fatty acids, lanolin, natural or synthetic oils or waxes and emulgators in the presence of water.
Further preferred embodiments are oily lotions based on natural or synthetic oils and waxes, lanolin, fatty acid esters, in particular triglycerides of fatty acids or oily-alcoholic lotions based on alcohols like ethanol or on glycols like propylene glycol and/or on polyols like glycerine and oils, waxes and fatty acid esters like triglycerides of fatty acids.
The dermatological or cosmetic composition of the invention can also have the form of an alcoholic gel containing one or more alcohols or polyols like ethanol, propylene glycol or glycerine and a thickener like diatomaceous earth, The oily-alcoholic gels can further contain a natural or synthetic oil or wax.
The solid sticks can contain natural or synthetic waxes and oils, fatty alcohols, fatty acids, fatty acid esters, lanolin and other fat bodies.
In the dermatological or cosmetic composition of the invention confectionated as an aerosol, generally usual propellants like alkanes, fluoroalkanes and chlorofluoroalkanes are used.
Further typical cosmetic application forms comprise lip sticks, lip care sticks, rouge, powder, emulsion and wax make-up as well as pre-sun and after-sun preparations.
All vehicles and adjuvants which can be used in the dermatological or cosmetic compositions of the invention are either known and commercially available or can be synthesized according to known processes.
The dermatological or cosmetic compositions of the invention can contain the vehicles and adjuvants mentioned above each in an amount in the range of from 0.001 to 30% by weight, preferably in an amount in the range of from 0.05 to 20% by weight and particularly preferably in an amount in the range of from 1 to 10% by weight.
The dermatological or cosmetic composition of the invention can be prepared by using processes which are known to an expert.
The conjugate of the invention can also be used to protect the skin, in particular to protect the Langerhans cells in the skin, to protect the DNA or to provide immunoprotection.
The conjugate of the invention can be used not only in cosmetics but also for example for the preparation of varnishes or security markings. In this case for example the group R1 in the general formula mentioned above can be a fluorescent group which can be excited by UV light.
The following examples illustrate the invention. The used starting materials are either commercially available or can be synthesized in a known manner.